Add setting for SNTP server

main/Kconfig.projbuild

@@ -11,6 +11,9 @@ menu "Bedside clock settings"
      config DEFAULT_TIMEZONE
             string "Default timezone"
             default "Europe/London"
+     config DEFAULT_SNTP_SERVER
+            string "Default SNTP server domain"
+            default "pool.ntp.org"
      config WIFI_MAX_RETRIES
             int "Maximum number of times to retry connecting to WiFi network"
             default 10